Answer is
3) how much mass per unit of volume is in a substance
Answer:
Nuclear fusion plays an important role in making elements that are heavier than helium.
Explanation:
Nucleosynthesis is the process by which new atomic nuclei are created from pre-existing nucleons (protons and neutrons) and nuclei. According to current theories, the first nuclei were formed a few minutes after the Big Bang, through nuclear reactions in a process called Big Bang nucleosynthesis.
In order to synthesize a new element, there must be a change in the number of protons. We should remember that elements are known by the number of their protons as it represents their atomic number.
Elements heavier than helium are formed by nuclear nucleosynthesis in which nuclear fusion plays a very crucial role as typified by the equations shown in the question.
Answer:
a) Mass = 3.9 g
b) Mass = 0.395 g
Explanation:
Density is related to the mass and volume of a substance by the relation:

a) Given:
Volume = 4.00cm3
Density = 0.97 g/cm3
Based on equation (1)

b) Given:
Volume = 125 ml
Density = 3.16 g/L
1 ml = 0.001 L
Therefore, 125 ml = 0.125 L
Based on equation (1)

0.498 moles of copper(II) phthalocyanine would be produced by
the complete cyclotetramerization of 255 grams of phthalonitrile in the
presence of excess copper(ll) chloride.
<em>Copper(ll) phthalocyanine (Cu(C₃₂H₁₆N₈)) is produced by the cyclotetramerization of phthalonitrile (C₈H₄N₂) according to the following reaction: 4 C₈H₄N₂(l) + CuCl₂(s) → Cu(C₃₂H₁₆N₈)(s) + Cl₂(g) How many moles of copper(II) phthalocyanine would be produced by the complete cyclotetramerization of 255 grams of phthalonitrile in the presence of excess copper(II) chloride?</em>
Let's consider the following balanced equation.
4 C₈H₄N₂(l) + CuCl₂(s) → Cu(C₃₂H₁₆N₈)(s) + Cl₂(g)
The molar mass of C₈H₄N₂ is 128.13 g/mol. The moles corresponding to 255 g of C₈H₄N₂ are:

The molar ratio of C₈H₄N₂ to Cu(C₃₂H₁₆N₈) is 4:1. The moles of Cu(C₃₂H₁₆N₈) produced from 1.99 moles of C₈H₄N₂ are:

0.498 moles of copper(II) phthalocyanine would be produced by
the complete cyclotetramerization of 255 grams of phthalonitrile in the
presence of excess copper(ll) chloride.
You can learn more about stoichiometry here: brainly.com/question/22288091
Answer:
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Explanation:
it will tell you what you need to know